1. Field of the Invention
The present invention relates generally to area of radio communication, and more specifically, to transmitting/receiving systems for transmitting and receiving broadband digital signals, such as broadcast TV, high-speed data exchanged over wireless network, etc.
2. Description of the Related Art
FIG. 1 is a block diagram illustrating a conventional transmitter/receiver, e.g., a conventional cell phone. FIG. 2 is a block diagram illustrating another conventional transmitter/receiver, as described in U.S. Pat. No. 6,754,508.
The conventional transmitter/receivers, as illustrated in FIGS. 1 and 2 have two major drawbacks.
First, a high level of broadband digital noise is generated by digital transmitting/receiving modules. A portion of the given noise, which is concentrated inside of the demanded bandwidth of the radio-frequency channel, directly contributes to input noise of the transmitter/receiver and worsens its noise-factor. For portable transmitter/receivers, such cell phones, the situation is even worse, as the antenna is positioned too close to a digital part of the transmitter/receiver. Consequently, a filter cannot remove the digital noise, as this noise is in-band.
Second, when receiving a signal in complex conditions of multibeam distribution of the signal, which is typical for distribution in a city and inside of buildings, it is inconvenient to use Multiple Input Multiple Output (MIMO) technology and/or technology that utilizes separate receiving of a signal in mobile devices, as the distance between multiple antennas cannot be great enough, for example, for a mobile receiver, such as a cell phone. Thus, correlation between two input signals from two antennas will be very high.